1. Technical Field
This invention is directed toward a system and method for creating editable whiteboard content. More specifically, the invention is directed toward a system and method for converting an image of a whiteboard into an editable electronic document.
2. Background Art
Meetings constitute a large part of many workers' working time. Making more efficient use of this time spent in meetings translates into a big increase in productivity.
Many meeting scenarios use a whiteboard extensively for brainstorming sessions, lectures, project planning meetings, patent disclosures, and so on. Note-taking and copying what is written on the board often interferes with many participants' active contribution and involvement during these meetings. As a result, some efforts have been undertaken to capture whiteboard content in some automated fashion.
Several technologies have been developed to capture the whiteboard content automatically. One of the earliest, the whiteboard copier, is a special electronic whiteboard with a built-in copier. With a click of a button, the whiteboard content is scanned and printed. Once the whiteboard content is on paper, it can be photocopied, faxed, put away in the file cabinet, or scanned into digital form.
More recent technologies attempt to capture the whiteboard content in digital form from the start. They generally fall into two categories—those that capture images of the whiteboard and those that track pen location and infer whiteboard content therefrom.
The devices in the first category capture images of the whiteboard directly. National Television System Committee (NTSC)-resolution video cameras are often used because of their low cost. Since these cameras usually do not have enough resolution to clearly capture what is written on a typical conference room size whiteboard, several video frames must be stitched together to create a single whiteboard image. Another device in this first category is the digital still camera. As high-resolution digital cameras get cheaper, taking snapshots of the board with a digital camera may become a popular choice. However, photographs of a whiteboard are often difficult to read because of light reflections and skewed camera angles relative to the whiteboard. Additionally, such snapshots are not editable in typical office productivity software such as word processors, databases, drawing programs and the like.
Devices in the second category track the location of the pen used to write on the whiteboard at high frequency and infer the content of the whiteboard from the history of the pen coordinates. Sometimes they include an add-on device attached to the side of a conventional whiteboard and use special cases for the dry-ink pens and eraser. Each pen emits ultrasonic pulses when pressed against the board. Two receivers at the add-on device use the difference in time-of-arrival of the audio pulses to triangulate the pen coordinates. Since the history of the pen coordinates is captured, the content on the whiteboard at any given moment can be reconstructed later. The user of this type of whiteboard recording can play back the whiteboard content like a movie. Because the content is captured in vector form, it can be transmitted and archived with low bandwidth and small storage requirements.
Electronic whiteboards also use pen tracking technology. They go one step further than the systems using the previously discussed add-on devices by making the whiteboard an interactive device. The user writes on a monitor with a special stylus that is tracked by the computer. The computer renders the strokes on the screen wherever the stylus touches the screen—as if the ink is deposited by the stylus. Because the strokes are computer generated, they can be edited, re-flowed, and animated. The user can also issue gesture commands to the computer and show other computer applications on the same screen.
Electronic whiteboards, however, currently still have limited installation base due to their high cost and small sizes (the size of an electronic whiteboard rarely exceeds 6 feet in diagonal). Furthermore, systems with pen-tracking devices have the following disadvantages: 1) If the system is not on or the user writes without using the special pens, the content cannot be recovered by the device; 2) Many people like to use their fingers to correct small mistakes on the whiteboard instead of the special eraser. This common behavior causes extra strokes to appear on the captured content; 3) People have to use special dry-ink pen adapters, which make them much thicker and harder to press, for some of the devices; and 4) Imprecision of pen tracking sometimes causes mis-registration of adjacent pen strokes.
It is noted that in the remainder of this specification, the description refers to various individual publications identified by a numeric designator contained within a pair of brackets. For example, such a reference may be identified by reciting, “reference [1]” or simply “[1]”. A listing of the publications corresponding to each designator can be found at the end of the Detailed Description section.